Twist drill gauge



March 27, 1951 N. H. swANsoN TWIST DRILL GAUGE Filed July 7, 1949 ra/lawn Patentecl Mar. 27, 1951 UNITED STATES RATENT OFFICE TWIST DRILL GAUGE Nels H. Swanson, Chicago, Ill.

Application July 7, 1949, SerialyNo. 103,414

10 Claims. l

The present invention relates to twist drill gauges and more particularly to a gauge embodying adjustable means for gauging the several angles on the point of a twist drill.

The clearance angle, chisel point angle, and point angle of twist drills should be ground to definite angles which vary in accordance with the type'of material the drills are designed to be used upon. For general all-around usefulness a twist drill gauge should include gauge members for gauging all these angles which are adjustable so that the gauge may be used for drills designed for drilling different kinds of materials.

Accordingly an object of the invention is to provide a new and improved twist drill gauge embodying gauge members for measuring all angles on the point of a twist drill, which gauge members are adjustable so that the gauge may be used to gauge twist drills of the varying angularities found in drills for drilling different kinds of ling a body so constructed that twist drills may be iirrnly held in gauging position relative to the body of the gauge member manually and without the need for special clamping or holding means.

A still further object of the invention is the provision of a new and improved twist drill gauge which is exceedingly simple in construction. and easy to use and which may be made from sheet metal stampings so that it is relatively inexpensive to construct but which nevertheless is accurate and entirely satisfactory in use.

These and other objects, advantages and capabilities of the invention will become apparent .from the following description, reference being had to the accompanying drawings, in which:

Fig. 1 is a side elevational View of the improved .gauge of the present invention showing it being used-to gauge the clearance angle on the point of 'atwist drill;

Fig. 2 isa View similar to Fig. l on a slightly venlarged scale showing the gauge being used. to

gauge the point angle on a twistv drill;

'l 3 is a View similar to Fig. 1 showing the gauge being used to gauge the chisel point angle on a twist drill;

4 is an elevational view of the front or inner of the gauge with a twist drill in phantom positioned therein;

Fig. 5 is an end view of the gauge taken in the direction of the arrows on line 5--5 of Fig. 4; andy Figs. 6 8 are views showing the various angles on a drill point which may be gauged with the gauge of the present invention.

The gauge of the present invention comprises a body member i0 including a sheet metal stamping I2 in the form of an angle strip and a second stamping le secured to the angle strip, upon the facing sides of which a pair of stamped sheet metal gauge members it and I8 are mounted. Stamping I2 has longitudinally extending side walls or flanges 25 and 22 (Fig. 5) in substantially perpendicular planes While mounting member Irl, which is somewhat shorter, has a pair of flanges 2li and 26 lying in planes dening an included angle of approximately Flange 2&5 on the mounting member I is spot welded or otherwise suitably xed to the outermost side of ange with its longitudinal edge 23 parallel with but set back slightly from the edge on the iiange 22, and with its iiange 22% extending outwardly from the bight in angle strip I2 in a plane substantially bisecting the angle between flanges 2B and 22 on angle strip (Fig. 5). By reason of this mounting of stamping irl, a ledge 3c is formed along the lateral edge of the body of the gauge which constitutes one or the gauging surfaces of the gauge. Y

The upper end of liange 26 on the mounting member I4 coincides with the upper edge of the flange 22 on the angle strip. However, the upper end of flange 24 on this mounting' member projects Vbeyond the end oi iiange 25 to form a mounting for the gauge member It.

Gauge member It which is used in gauging the point anglevof a drill point is of generally bell crank shape and has a pair of arms 35i and Vlnternfiediate its ends it is pivotally secured. by

means of a rivet 33 to the projecting part of the '.fiange 2e on the mounting member lil. Arm 3ft of this gauge member projects inwardly of the bight portion of the angle strip i2 in a plane substantially bisecting the angle between the flanges 2G and 22 and has an acutely inclined lower edge provided with an integral flange f Fig. 4) in a plane substantially perpendicular to the plane of the arm 34. The other arm 36 of gauge member I 6 forms a pointer to indicate upon a graduated scale 42 embossed in the iiange 2t on mounting `member I4. Since the point angles on drills for Various types of? materials vary betweeniapproximately 45 and 75, scale 13 is marked off to-indicate angles in this range.

The second gauge member I 8 is pivotally secured adjacent the upper end of the body of the gauge by means of a rivet lili. Preferably the inner end of the rivet i4 is countersunk in the I'iange 22 on the angle strip l2 so that the inner side of the body member it is free of projections which might 4interfere with the proper positioning oi a drill relative to the gauge. When the gauge member it is rocked to its outer limit, its top edge fle lies substantially in the plane of the upper end of the flanges 2t and 22 on the angle strip i2. Adjacent its `upper end an outwardly projecting ear 38 is provided along the outer edge of gauge member IS. This ear has an edge 13S inclined at an obtuse angle to the ledge 3S at all positions oi adjustment or gauge member i8.

Gauge member i8 has a pointer iii) on its lower end which indicates on a graduated scale 52 embossed in the ilange 2; on mounting member id. This scale is marked oil to indicate angles from approximately 126 to 135 and is used to measure the chisel point angle or" a drill, the variation in degrees between the chisel point angles oi' drills for various purposes lying in this range.

A second pointer 5e is formed in a stampedl,out portion 5d intermediate the ends of gauge member i8. This pointer indicates on a second graduated scale 53, also embossed in the ange 26 on stamping le. This scale, which is used in measuring the clearance angle of a drill is marked off in angles running from approximately `6o to `The variation in clearance angles on drills for various purposes normally falls within this range,

In order to clarify the manner in which the gauge is used, and the various angles on a twist drill which may be measured by this gauge, these angles have been shown and labeled on the portion of a drill point disclosed in Figs. 6, and 8.

In gauging the point angle, the pointer on the end oi arm 35 on gauge member is set at the angle to which it is desired to grind the cutting edge of a drill, for example, at 59. The drill to be ground is then pressed against the inner sides oi the flanges 2d and 22 on body member it (Figs. 2 and 5) with the thumb of the use-rs left hand while the first two ngers of this hand extend around the baci: side of body member l and are pressed `against the outer edge of flange 2d. As a result, the axis of the drill will be at a xed position relative to the body member lil. With the drill held in this position it is .rotated and moved axially with the right hand until one or its cutting edges lies in a plane substantially parallel with the edge of gauging flange di: on gauge member i6 and is in contact with this gauging surface. By viewing the gauging surface 6B against a light, it can be determined whether or not more grinding is required and which parts of the cutting edge require grinding. rThis same process may be repeated for the second cutting edge of the drill. Movement of the gauge inembers i6 and I8 is restrained sufficiently by the tightness-'of rivets -38 and lil to prevent accidental movement of these gauge members from a set position while a drill point is being `gauged..

With the drill .and gauge in the position mentioned above, it is possible to determine whether the drill point has been ground to the proper clearance angle while the drill is, in the same position relative to the gauge. To do this, the left hand is turned slightly so as to bring the upper edge i6 of the gauge member l directly into the line of vision of the operator. The line indicated at d@ in Fig. 2, which line determines the clearance angle oi' the drill point, will then be readily visible, and, if it is parallel with the top edge Il@ of gauge member I8 and this gauge member has previously been set t0 the proper clearance angle, then the user will know that he is grinding the drill at -the proper clearance angle.

A fairly accurate reading may be secured in this way, but a more accurate reading will be obtained if the drill is lowered relative to the body member it :far enough to bring ledge 'es substantially to the level or the upper yedge $25 or the gauge member i8. By sighting across this upper edge toward the edge Eil on the drill point, a very accurate determination oi the clearance angle of the drill point can be made. Since this method o gauging the clearance angle is more accurate, it is preferred.

In gauging the chisel point angle oi a drill, the scale :i2 and polntei et* on the lower edge of gauge member i8 areused and the body mimber ll preferably is held in the right hand in such a manner that the ,gauge member may be manipulated with the thumb if desired, although ordinarily in gauging the chisel point angle of a drill the ygauge member ,I3 will rst be set at the proper position. One .of the cutting edges of the drill is then placed upon the ledge Se formed along the lateral vedge of the body member iii. rthis brings the chisel point of the `drill into a position facing the inclined edge 49 .on the gauge member i8.. The drill may then be moved to bring the chisel point against this inclined edge and, by viewing the gauge preferably against a light, it can be determined whether the chisel point on the drill lines up with the inclined edge l and thus whether the drill point has been ground to the desired chisel point angle.

The use of the gauge in grinding the points of drills to particular angles has been described above. When used for this purpose, the gauge members l and IS are preset at the angles vdesired. However, the gauge may also be used to measure the angles on a drill point where these are unknown, `in which case the gauge members and drill are moved relatively until the gauging surfaces and the edges to be measured on the drill are brought into register. The angles of these edges may then be read on the proper scales.

From the above description of the construction and operation of the gauge, its simplicity and ease or operation will be apparent. This simplicity is secured in part by the construction of the body in which the stamping I4 forms a mounting for gauge member i5 and also cooperates with the angle stamping i2 to denne the ledge 35 which forms one of the gauging surfaces. Furthermore the gauge members I'S and it are so arranged on the body member Il] that a good estimate of the clearance angle of the drill point can be made when the drill is in position to have its point angle gauged. Moreover, the gauge member EB not only has an edge 46 for gauging the clearance angle of the drill point but also has an inclined edge 59 on the ear 48 cooperating with the ledge 3U on body member IG in gauging the chisel point angle of a drill.

While I have shovim and described a preferred embodiment of my invention, it will be apparent that numerous variations and modications thereof may be made without departing from the underlying principles of the invention. I, thereier-e, desire, by the following claims, to include within the scope of the invention all such variations and modifications by which substantially the results of my invention may be obtained through the use of substantially the same or equivalent means.

I claim:

1. A device for gauging twist drills comprising a body member having elongated angularly disposed side wall structure adapted to cooperate with the periphery of a drill pressed against-the same to hold the vdrill in gauging relation with the body, means forming a flange extending outwardly of the side Wall structure, means forming a ledge along one side of said wall structure, an adjustable first gauge member secured to said outwardly extending flange having ay gauging surface for gauging the point angle of a drill positioned against said side wall structure extending across the axis of said drill at an acute angle thereto, a second adjustable gauge member secured on the outer sideof said side wall structure and having a gauging surface along one end thereof for gauging the clearance angle of a drill in gauging position relative to said body member and a second gauging surface on the outer edge thereof to cooperate with said ledge in gauging the chisel point angle of a drill, the cutting edge of which is engaged upon the ledge,

and cooperating means on said body member and on said gauge members to indicate the angles gauged by said gauging surface.

2. A device for gauging twist drills comprising a body member having elongated side Walls disposed at an angle and adapted to cooperate with the periphery of a drill pressed against the same to hold the axis of a drill at a fixed position relative to said body, a mounting member having a first flange secured in superposed relation to the outer side of one of said side walls, said flange having a lateral edge parallel to the lateral edge of the said side wall and offset from end to end relative thereto to define a ledge, and a second flange on said mounting member extending outwardly of said side wall structure, a first gauge member on the outwardly extending ange for gauging the cutting edge of a drill having its axis at the said fixed position, a second gauge member on the outer side of the other flange of said mounting member having a gauging surface along one end thereof for gauging the clearance angle of a drill having its axis at the said fixed position, and a second gauging surface on the outer edge thereof to cooperate with the ledge in gauging the chisel point angle of a drill, the cutting edge of which is engaged upon said ledge, and cooperating means on the inwardly facing sides of the two flanges on the mounting member and on said gauge members to indicate the angles gauged by said gauging surfaces.

3. A device for gauging twist drills comprising a body member including an elongated angle strip, the inwardly facing sides of which are adapted to cooperate with the periphery of a drill pressed against the same to hold the drill in gauging relation with the body, a mounting member having a flange extending outwardly of the bight of said angle strip ina plane bisecting the angle between the sides thereof and a flange adapted to be secured in superpcsed relation to the outer side of one flange on said angle strip for securing the mounting member thereto, the lateral edge of said second iiange of the mounting member lying parallel to the lateral edge of the flange on said angle strip to which it is secured and being offset therefrom to denne a ledge, a rst gauge member pivotally secured to said outwardly extending flange having a gauging surface for gauging the cutting edge of a drill disposed in gauging relation to said body, a second gauge member on the outer side of the mounting flange of said mounting member pivotable relative to said body member an-d having a gauging surface along one end thereof for gauging the clearance angle of a drill in position to have its cutting edge gaugedfandasecond -disposed side walls to cooperate with the sides of a drill to be gauged for maintaining the axis of said drill in a fixed position relative'to said body member, a gauge member pivotally secured to the outermost side of one of the side walls of said body and having a first gauging surface in a plane parallel to said one side wall and extending beyond one end of the same for gauging the clearance angle of a drill at gauging position, a first graduated scale on the outermost side of said one side wall, a first pointer on said gauge member to register on the scale the clearance angle gauged by said first gauge surface, .means forming a ledge along the lateral edge of the said one side wall of said body member toI receive the cutting edge of a drill for locating the chisel point of the drill for gauging, a second gauging surface on said gauge member disposed at an obtuse angle to said ledge at all positions of the gauge member for gauging the chisel point angle of a drill held in gauging relation thereto, a second graduated scale on the Loutermost side of said one side wall, and a second pointer on said gauge member to register on the second scale the chisel point angle of said drill.

5. A device for gauging twist drills comprising a body member having wall structure to cooperate with the sides of a drill -to be gauged for maintaining the axis of said drill in a fixed position relative to said body member, a gauge member pivotally secured to said body member and having a first gauging surfacefor gauging the clearance angle of a drill in gauging position, a first graduated scale on saidbody member, a first pointer on said gauge member to register on the scale the clearance angle gauged by said first gauge surface, means forming a gauging surface on said body member to receive the cutting edge of a drill for `locating the chisel point of said drill for gauging, a second gauging surface on said gauge member disposed at an obtuse angle to the gauging surface on said body member at alllpositions of the gauge member for gauging the chisel point angle of i a drill held in gauging relation with said gauging surfaces, a second graduated scale on said body member, and a second pointer on said gauge member to register on the second scale the chisel point angle of said drill.

6. A device for gauging twist drills comprising a body member having elongated side wall structure to cooperate with the periphery of a drill for maintaining the axis thereof at a fixed position relative tothe body memberwhen the drill is pressed against said wall "structure, a

first gauge member adjustably secured to the body member having a gauging surface beyond one end of said body extending across the axis cf a drill positioned against said wall structure at an acute angle to said axis, saiddrill, body member and gauge member being relatively adjustabie to bring a cutting edge of said drill and said surface into gauging relation, a second gauge member adjustably secured to said body member and having a gauging surface along one end thereof brought, into gaugingrelation with, the

clearance angle of the drill by relative movement of the drill, body member andv gauge member, means on the body member and first and second gauge members lorv indicating respectivelythe point angie and clearance angle o the point of said drill, means forming cooperating gauging surfaces on said body member and a lateral edge of the second of said gauge members adapted against the same to maintain the axis of the drill in fixed position relative vto said body .member while the point angle and clearance angle of said drill are being gauged, a pair of gauge members pivotally secured to said body member, a gauging surface on the rst gauge member for gauging the cutting edge of the drill at gauging position, a first gauging surface on said second gauge member for gauging the clearance angle oi a drill in gauging position, means on the body member and iirst and second gauge members ier indicating respectively the point and clearance angles gauged by said two gauge members, means forming a projecting edge along one side of said body member to receive the cutting edge of a drill for positioning its chisel point for gauging, a gauge surface on said second gauge member disposed at an obtuse angle to said projecting edge at all positions of the gauge member for gauging the chisel point angle of a drill in. gauging position on said edge, and a graduated scale on said body member and a pointer on said second gauge member to indicate on said scale the chisel point angle of said drill.

8. A device for gauging twist drills comprising a body member having elongated flat anguvlarly disposed sides to cooperate with the side of a drill to be gauged for maintaining the axis thereof in a fixed position relative to said body member, a gauge member pivotally secured adjacent one'y end of said body member and having a gauging surface extending at an acute angle to the axis of said drill over the space between said sides in a plane substantially bisecting the angle therebetween, said gauge member, body member and drill being relatively movable to bring said gauging surface into gauging relation with a cutting edge cf said drill, a second gauge member pivotally secured to said body and having a gauging surface in a plane parallel with the plane of one of said sides and below said first mentioned gauge surface for gauging the clearance angle of a drill held in position forv gauging its cutting edge, cooperating means including graduated scales on said body member and pointers on said gauge members respectively to indicate on said scales the angles gauged by said gauging surfaces, cooperating gauging surfaces incuding a gauging surface along one side edge of said body member and a gauging surface on said second gauge member disposed at an obtuse angle to said edge at all positions of the gauge member for gauging the chisel point angle of a drill held in gauging relation to said gauging surfaces, and means including a third graduated scale on said body member, and an additional` pointer on Asaid second gauge -mernber to indicate the chisel point angle on said third scale.

9. A device for gauging twist drills comprising av body member having wall structure against which the periphery of a ldrill may be pressed to maintain the body and drill in gauging relation while the point angle and clearance angle of said drill are being gauged, a pair of gauge members secured to said body member, a gauging surface on the Hirst gauge member `to gauge the Acutting edge of a drill in gauging position relative to the body, a first gauging surface on the second gauge member for gauging the clearance angle of said drill, cooperating surfaces for gauging the chisel point angle of a drill including a gauging surface on the body and a second gaugingy surface on the second gauge member adjustable relative to 'the gauging surface on the body member by pivotal movement of said second gauge member, and means including three 'graduated scales on said body member, one pointer on said rst gauge member and two pointers on said second gauge vmember to indi-cate on said scales the angles gauged by said gauge members.

` 10. A twist drill gauge, comprising a sheet metal angle guide forming a V-s'naped channel to receive a twist drill for gauging its point and clearance angles, the guide having a pair of legs terminating in longitudinal edges and intersecting at an apex, a sheet metal bracket secured to the guide having a leg extending outwardly from the apex of the guide approximately to bisect the exterior angle deiined by the guide, a point angle gauge lever pivoted on the leg oi the bracket having an upper arm extending inwardly over one end of the guide to register with the point angle of a drill and having a lower pointer arm for in'- dicating' the point angle, the bracket leg vhaving an angular scale adjacent the pointer'arm, a l'seeond sheet metal lever pivoted on the angle guide adjacent its upper end for measuring the clearance and chisel point angles of a drill, the second lever having a transverse edge protruding beyond the upper end of the angle guide to register with the clearance angle of a drill positioned for gauging its point angle, the second lever having la-'seeond edge protruding beyond a longitudinal edge of the angle guide at any adjustable obtuse angle for gauging the chisel point angle of a drill positioned with a cutting edge aligned with the longitudinal edge of the guide, the second lever having a downwardly extending arm terminating in a rst pointer and having an aperture shaped to provide a second pointer, and a pair of scales being provided on the angle guide adjacent the second gauge lever pointers, one of the pointers on the second lever indicating the clearance angle and the other indicating the chisel point angle.

NELs H. swANsolv.

REFERENCES CITED The following references are of record in the file of this patent:

UNITEDY STATES PATENTS Number Name Date 609,895 lVi'ithell Aug. Se, 1898 2,301,256 Conners Nov. 10, 1942 2,337,819 Hofmann Dec. 28, 1943 2,377,715 Poncelet June 5, 1945 FOREIGN PATENTS Number Country Date 606,459 Great Britain Aug. i3, 194B 

